Proceedings of the 10th International Colloquium on Paratuberculosis

#43 A comparison <strong>of</strong> skin test, ELISA and mycobacteriologic examination in detection <strong>of</strong>
Map-exposed heifer calves: a field study
Charles O Thoen, Meredith C Johns, David A Gibbs, Jerald L Jarnagin
Iowa State University, USA
Johne’s disease is present in a high percentage <strong>of</strong> dairy herds and causes major economic losses to <strong>the</strong> dairy
industry. Diagnostic tests for detecting serum antibody are not <strong>of</strong> suitable sensitivity for monitoring M. avium ss
paratuberculosis (Map) infection in young replacement cattle or for detecting subclinical infection in cattle. The
specific objectives were to: 1. Obtain information on skin test responses in heifers from Map positive herds,
and 2. Determine <strong>the</strong> specificity <strong>of</strong> skin tests using Map PPD in heifers 10 to 26 months <strong>of</strong> age.
The MAP-PPD used in this investigation was prepared by precipitation with trichloroacetic acid (TCA)
from <strong>the</strong> culture filtrate <strong>of</strong> Mycobacterium avium ss paratuberculosis ATCC Neotype Strain 19698. The skin test
was conducted in <strong>the</strong> mid-cervical region; skin thickness measured (mm) before injection <strong>of</strong> PPD and 72 hours
following injection. Skin tests were conducted in 842 heifers were from 10 herds in which Johne’s disease had
been diagnosed by mycobacteriologic examination and in 468 heifers <strong>of</strong> <strong>the</strong> same age which were from 16
herds in which Johne’s disease had not been diagnosed.
The results revealed that positive skin test responses were detected in heifers 10 to 26 months <strong>of</strong> age
in each <strong>of</strong> <strong>the</strong> 10 Johne’s positive herds; positive ELISA reactions were detected in heifers in only 3 <strong>of</strong> <strong>the</strong> 10
Johne’s positive herds. The specificity <strong>of</strong> <strong>the</strong> skin test using Map was 98% in heifers 10 to 26 months <strong>of</strong> age,
95% in cows 26 to 38 months <strong>of</strong> age and 97% in cows 38 to 50 months <strong>of</strong> age.
#57 Expert-survey on basically management suggestions for MAP-positive farms
Johannes Lorenz Khol, Walter Baumgartner
Clinic for Ruminants, Department for Farm Animals and Veterinary Public Health, University <strong>of</strong> Veterinary Medicine
Vienna, Austria
Beside <strong>the</strong> ongoing discussions about <strong>the</strong> improvement <strong>of</strong> laboratory procedures, <strong>the</strong> genome <strong>of</strong> MAP and
o<strong>the</strong>r important scientific topics a supraregional discussion about a basically on farm program against paratuberculosis
should be started.
Many different countries have established voluntary programs to control paratuberculosis and prevent
fur<strong>the</strong>r spreading <strong>of</strong> <strong>the</strong> disease. In o<strong>the</strong>r countries compulsory registration for paratuberculosis is performed,
or strict control and stamping out programs are in action.
To start <strong>the</strong> discussion and try to find agreement on cost effective and easy to perform steps to fight paratuberculosis,
we would like to perform an expert-survey during <strong>the</strong> <strong>10th</strong> ICP on basically management suggestions
for MAP-positive farms. We suggest that <strong>the</strong> survey is introduced in a short presentation at <strong>the</strong> beginning
<strong>of</strong> <strong>the</strong> congress and carried out during brakes and poster sessions.
The aim <strong>of</strong> this survey is to generate effective and simple measurements to reduce <strong>the</strong> incidence <strong>of</strong> paratuberculosis
in affected herds. This should be <strong>the</strong> possible start <strong>of</strong> a trans-national basic program in <strong>the</strong> fight
against paratuberculosis and <strong>the</strong> protection <strong>of</strong> free herds and areas which could be implemented immediately.
Beside all differences in actions and opinions this could be considered as a “minimum level” which could
be achieved in reasonable time and would be accepted by many countries.
Results <strong>of</strong> <strong>the</strong> survey could be presented in <strong>the</strong> IAP Paratuberculosis Newsletter.
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